1. Field
The following description relates to a power amplification apparatus, and such as to a power amplification apparatus using a dynamic bias modulator.
2. Description of Related Art
Recent wireless communication systems use a modulation method having high peak to average power ratio (PAPR), such as orthogonal frequency division multiplexing (OFDM), so as to efficiently use limited frequency resources and also process a large amount of data.
In a modulation method having high PAPR, in order to maximize efficiency, a power amplifier (PA) may be implemented as a highly efficient PA, e.g., Class C, D, E or F amplifier. Although such power amplifiers (PAs) can operate at high efficiency in a compression region, i.e., a saturation region, they require an additional linearization technique due to the nonlinearity of the compression region, which reduces efficiency of the overall system.
Furthermore, although PAs in class C, D, E or F operate at high efficiency, the efficiency of the PAs is less at a region lower than a maximum power point, i.e., a back-off region. During most of operating periods, wireless communication systems operate in the back-off region, which results in lower average power ratio.